<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style media="screen">
    .box100{
      width: 100px;
      height: 100px;
      border: 1px solid black;
      background-color: #cccccc;
      margin: auto;
      transition: all 1s;
    }
  
    #d2:hover{
      transform: scale(2);
      background-color: rgba(255, 0, 0, 0.2);
    }
  
    #d3:hover{
      transform: scale(0.5);
      background-color: rgba(0, 255, 0, 0.2);
    }
  
  </style>
</head>
<body>
  <div class="box100" id="d1"></div>
  <div class="box100" id="d2"></div>
  <div class="box100" id="d3"></div>
</body>
</html>